1. Field of the Invention
The present invention relates to novel piperidine derivatives and pharmacologically acceptable salts thereof which have an antihistaminic and antiallergic activity and are useful for the treatment of, for example, bronchial asthma, allergic rhinitis, dermatosis, and urticaria, and to the method for preparation thereof.
The present invention also relates to a pharmaceutical composition comprising the effective amount of the same.
2. Description of the Prior Art
Among antihistaminic agents having diphenylmethoxypiperidine ring in their molecules, diphenylpyraline (The Merck Index, 11th edition, 3334) represented by the following formula: ##STR2## has been developed as a clinically available drug and is used for the treatment of such ailments as allergic rhinitis and dermatosis.
Japanese Unexamined Patent Publication No. 228059/1987 discloses TMK-688 (N-[2-[4-(diphenylmethoxy)piperidino]ethyl]-5-[4-(ethoxycarbonyloxy)-3-met hoxyphenyl]-2,4-pentadienoylamide) represented by the following formula: ##STR3##
However, neither of the above discloses the compounds of the present invention.
A large number of antihistaminic agents have been developed so far and are used for the treatment of, for example, allergic dermatosis or rhinitis. However, adverse reactions of a central inhibitory action caused by the administration of the known antihistaminic agents such as sleepiness or sedation is found to be a great problem with these known agents. In addition, an anticholinergic action which is considered to be one of the possible reasons for hydrodipsia or mydriasis is another undesired adverse reaction of the antihistaminic agents. Various kinds of research have been conducted to solve the above problems, however, presently available antihistaminic agents are insufficient from a clinical point of view.